Research progress on the preparation of cobalt-based oxide catalysts with different morphologies and their application for catalytic purification of air pollutants

Abstract

The removal and purification of air pollutants are urgently required because of the significant harm posed to humans and the environment. Air pollutants can be broadly categorized into two classes: particulate and gaseous pollutants. Particulate pollutants primarily consist of soot particles, dust, and other small solid particles. Gaseous pollutants mainly comprise nitrogen oxides (NOx), carbon monoxide (CO), volatile organic compounds (VOCs), ozone (O3), and sulfur dioxide (SO2). Catalytic oxidation technology provides an efficient and cost-effective method for purifying air pollutants. This technology emphasizes the rational design and synthesis of high-performance catalysts, thereby emerging as a research hotspot. In recent years, numerous catalysts have been employed for the catalytic purification of air pollutants. Transition metal oxide catalysts have been studied extensively owing to their low cost and impressive catalytic activities. Among them, cobalt-based oxide catalysts stand out for their remarkable performance in the catalytic purification of air pollutants. In this paper, the preparation of cobalt-based oxide materials with unique morphologies, including flower-like, rod-like, hollow, and three-dimensional ordered macropores (3DOMs), is discussed. Subsequently, research progress on cobalt-based oxide catalysts for removing air pollutants such as NOx species, soot particles, VOCs, CO, O3, and SO2 are introduced in detail. Finally, the challenges and development trends of cobalt-based oxide catalysts for the catalytic removal of air pollutants are explored, and future research directions are proposed.